U.S. patent number 4,605,202 [Application Number 06/656,882] was granted by the patent office on 1986-08-12 for ball valve.
This patent grant is currently assigned to Asahi Yukizai Kogyo Co., Ltd.. Invention is credited to Nitiro Sano, Kazuhiko Tsuno.
United States Patent |
4,605,202 |
Tsuno , et al. |
August 12, 1986 |
Ball valve
Abstract
A ball valve for controlling liquid flow that comprises a
tubular valve body, a ball rotatably built-in inside of the valve
body, a pair of unions screwed into opposite ends of the valve body
so as to be in slidable contact with the ball, and a pair of body
caps connected to outer ends of each union through a packing ring
for providing a water-tight seal therebetween. This valve have no
cavities therein which cavities tend to entrap the liquid during
the passage thereof. According to this construction the valve is
kept always clean and free from any contamination caused by the
putrescence of the entrapped liquid, even when used in the food
industry.
Inventors: |
Tsuno; Kazuhiko (Nobeoka,
JP), Sano; Nitiro (Nobeoka, JP) |
Assignee: |
Asahi Yukizai Kogyo Co., Ltd.
(Miyazaki, JP)
|
Family
ID: |
27311672 |
Appl.
No.: |
06/656,882 |
Filed: |
October 2, 1984 |
Foreign Application Priority Data
|
|
|
|
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Oct 28, 1983 [JP] |
|
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58-166050[U] |
Dec 8, 1983 [JP] |
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58-188583[U]JPX |
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Current U.S.
Class: |
251/315.13;
251/315.05; 277/609; 277/614; 277/626 |
Current CPC
Class: |
F16K
5/201 (20130101); F16K 5/0626 (20130101) |
Current International
Class: |
F16K
5/00 (20060101); F16K 7/12 (20060101); F16K
7/16 (20060101); F16K 5/20 (20060101); F16K
5/06 (20060101); F16K 005/06 () |
Field of
Search: |
;251/315,316
;277/167.5,27R,27A,211 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schwadron; Martin P.
Assistant Examiner: Novack; Sheri M.
Attorney, Agent or Firm: Burns, Doane, Swecker &
Mathis
Claims
What is claimed is:
1. A ball valve for controlling liquid flow, comprising a tubular
valve body, a ball rotatably mounted inside of said valve body and
provided with a central through channel, a union positioned in each
end of said valve body so as to be in slidable contact with said
ball via a seat, and a body cap connected to each outer end of said
union with a packing ring intervening therebetween for providing a
water-tight seal, said union and said body cap having opposed end
surfaces, said packing ring being accommodated in an annular groove
recessed on at least one of said opposed end surface, said body cap
being secured to said union by a cap nut engaged with a
circumference of said valve body, whereby liquid flow passing
through the valve is controlled by rotating said ball so that the
direction of the channel of said ball is varied from a direction
aligned with a longitudinal axis of said valve body to a direction
perpendicular to said axis of said valve body, said union having,
at the inner end thereof, an annular projection substantially
filling an annular cavity between an inner wall of said valve body
and an outer surface of said ball, said packing ring having the
same inner diameter as that of said union and is provided with an
annular rib to be accommodated into the entire length of said
annular groove, said ball valve including a valve stem connected to
said ball, said valve stem extending outwardly through said valve
body, a portion of each annular projection located adjacent said
stem when said channel is aligned with said axis.
2. The ball valve according to claim 1, wherein said annular
projection extends along the outer surface of said ball and has a
spherically concaved surface conforming with said outer
surface.
3. The ball valve according to claim 1, wherein said groove has a
rectangular cross-section and said rib has a cross-section
comprising a rectangle connected by a converged trapezoid to a base
surface of said rib so that said rib fills said groove.
4. The ball valve according to claim 1, wherein said union is
screwed into said end of said valve body and is provided with a
flange portion around the outer end thereof, said flange portion
having at least one recess on a circumference thereof for
cooperating with a tool to rotate said union so as to screw said
union relative to said valve body.
5. The ball valve according to claim 4, wherein four recesses are
provided around the flange portion at an angular distance of
90.degree. to each other.
6. A ball valve according to claim 1, wherein said packing ring
includes a planar base portion sealingly fitted between said
opposed end surfaces so as to entirely fill space between said
opposed end surfaces from said inner diameter of said union to said
annular groove.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a ball valve, in particular, it
relates to a ball valve made of plastic and suitable for
utilization in the food industry for transporting perishable
liquids or purified water.
2. Description of the Prior Art
The conventional ball valve, for example, as disclosed in Japanese
Unexamined Utility Model Publication (Kokai) No. 58-89656,
comprises, as illustrated in FIG. 1, a valve body 1 of a
cylindrical shape, a ball 2 accommodated in the valve body 1 and
having a through-channel in the central portion, a pair of unions
3, each attached to opposite ends of the valve body 1 so as to be
in slidable contact with the ball through a seat 9, and a pair of
body caps 4 each connected to the outer end of the unions 3 by
means of a cap nut 5. According to the above arrangement, a liquid
passage to be connected to the up- and downstream piping (not
shown) is formed through the valve by a central bore provided in
each of these elements, as shown in FIG. 1. The ball 2 can be
rotated by a handle 8 and a stem 7 through 90.degree. about its
axis to shut off the liquid passage, as illustrated in FIG. 2.
According to the above construction, an annular cavity A is left
between the union 3 and the ball 2. In use, liquid transported
through the valve gradually leaks into the cavity A through a
contact area between a seat 9 and the surface of the ball 2 and is
entrapped therein. This entrapped liquid may freeze and expand in
winter, resulting in breakage of the valve. This causes another
serious problem in that, when the valve is incorporated in the
piping system for food industry, the entrapped liquid may putrefy
because of the presence of bacteria and thus contaminate the entire
system. Further, when the transported liquid is purified water, the
purity of the entrapped water tends to be degraded over the lapse
of a period of time.
Another such cavity having a tendency to entrap the liquid resides
in the valve structure other than the above cavity A. That is,
there is a second cavity B between the end surfaces of the union 3
and the body cap 4. The cavity B is inherently formed because an
O-ring 10 for sealing a connection between the union 3 and the body
cap 4 must have a thickness larger than the depth of a groove 11
accommodating the O-ring 10 to ensure tight sealing. The second
cavity B directly entraps the liquid from the liquid passage, which
liquid entrapment results in the same drawbacks as those of the
first cavity A, even if the effects of the former are less than
those of the latter.
In some cases, for example, as disclosed in Japanese Unexamined
Patent Publication (Kokai) No. 57-37160, a further cavity C may
exist in the inside wall of the outer end of the union formed by
dents engageable with a special tool for screwing the union
relative to the valve body. The cavity C also has drawbacks similar
to those of the cavities A and B.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a ball valve
free from the above drawbacks of the prior art.
It is another object of the present invention to provide a ball
valve made of plastic, which has no cavities entrapping liquid to
be transported.
The above objects of the present invention are achievable by a ball
valve for controlling liquid flow comprising a tubular valve body,
a ball rotatably built-in inside of the valve body and provided
with a central through channel, a union screwed into each end of
the valve body so as to be in slidable contact with the ball via a
seat, and a body cap connected to each outer end of the union with
a packing ring intervening therebetween for providing water-tight
sealing, the packing ring being accommodated in an annular groove
recessed on the opposed end surfaces of the union and/or of the
body cap. The body cap is integrated to the union by means of a cap
nut screwably engaged with a circumference of the valve body. In
the present invention, the liquid flow passing through the valve is
controlled by rotating the ball so that the direction of the
channel of the ball is varied from a direction aligned with the
axis of the valve body to a direction perpendicular to the axis of
the valve body, the ball valve being characterized in that the
union has, at the inner end thereof, an annular projection
substantially filling up an annular cavity between the inner wall
of the valve body and the outer surface of the ball.
According to a preferred embodiment of the present invention, the
packing ring has the same inner diameter as that of the union and
is provided with an annular rib or ribs to be accommodated into the
entire length of the annular groove. Further, the rib or ribs of
the packing ring preferably have a cross-section consisting
substantially of a rectangle connected by a converged trapezoid to
a base surface of the rib.
In another embodiment of the present invention, the union of the
ball valve is provided with a flange having at least one recess on
the circumference thereof for cooperating with a tool to rotate the
union by screwing it relative to the valve body.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the present invention will be
apparent from the following description with reference to the
attached drawings, in which:
FIG. 1 is a sectional side view of a ball valve of the prior art
illustrating a passage open position of a ball;
FIG. 2 is a view similar to FIG. 1 illustrating a passage close
position of the ball;
FIG. 3 is a sectional side view of a ball valve of an embodiment
according to the present invention;
FIGS. 4 to 6 are sectional side view of parts of ball valves of
different embodiments according to the present invention,
illustrating a packing ring between a union and a body cap,
respectively;
FIG. 7 illustrates a preferable cross-section of a packing ring
according to the present invention;
FIGS. 8 and 9 are, respectively, a side view and a front view of a
union of a ball valve according to the present invention; and
FIG. 10 is a side view of a tool for rotating a union.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A first embodiment of the present invention is described with
reference to FIG. 3, in which the same reference numerals as FIGS.
1 and 2 are used for designating the same or corresponding parts
thereof.
The ball valve of the first embodiment comprises a hollow
substantially cylindrical valve body 1 made of a plastic such as
polyvinyl chloride. A ball 2 is accommodated in the valve body 1.
The ball 2 has a through channel 6 at a central portion threof and
is rotatable about an axis perpendicular to the channel by means of
a handle 8 connected to the upper part of the ball 2 by a stem 7
extending outward from inside the valve body 1. A hollow union 3 is
screwed into each of the opposite ends of the valve body 1. An
annular seat 9 made of a low friction material such as
polytetrafluoroethylene is provided on the inside surface of the
union 3 for providing a slidable contact with the circumference of
the ball 2. The seat 9 is backed up with an elastomeric seat 9a
and, thereby, can be resiliently pressed onto the ball 2 to form a
water-tight seal between the ball 2 and the union 3. According to
the present invention, the inner end of the union 3 extends to the
innermost region along the circumference of the ball 2 with a small
gap therebetween, to form an annular projection 3a. Therefore, a
cavity A shown in FIG. 1, which naturally existed in the prior art
valve between the ball 2 and union 3, can be filled by the
projection 3a having a concaved spherical inner surface
complementary to the circumference of the ball 2. The projection 3a
may be molded separately from the remaining part of the union 3 and
bonded thereto by adhesive. However, it is preferable to mold them
together as a one-piece part.
To eliminate the second cavity B between the union 3 and a body cap
4 connected to the outer end of the former, as stated in connection
with the prior art, a second embodiment of the present invention
shown in FIG. 4 has a unique packing ring 12 instead of a
conventional O-ring 10 (see FIGS. 1, 2 or 3). The packing ring 12
has an inner diameter "d" the same as that of the union 3 and also
has an annular rib 13 adapted to be tightly accommodated in the
entire length of an annular groove 11 recessed on the end surface
of the union 3 confronting the body cap 4. The packing ring 12 may
be made of a suitable elastomeric material, including natural and
artificial rubbers, in which styrene-butadiene rubber (SBR),
chloroprene rubber (CR), butadiene-acrylonitrile rubber (NBR),
ethylene-propylene rubber, and silicone rubber are preferable. A
height of the rib 13 from a base surface 14 of the packing ring 12
is preferably somewhat larger than the depth of the groove 11,
e.g., 0.2 to 0.3 mm.
The annular groove 11 may provided on the end surface of the body
cap 4 instead of or in addition to the end surface of the union 3.
These instances are illustrated in FIGS. 5 and 6, respectively, as
third and fourth embodiments of the present invention. In such
cases, of course, the packing ring 12 should have a rib or ribs
having a size and cross-section matching those of the grooves.
The cross-section of the rib 13 may be of any shape, such as
rectangular or semi-circular, provided good sealing can be
obtained. However, it has been found that, as shown in FIG. 7, a
rib consisting of a rectangle 15 connected by a converged trapezoid
16 to the base surface 14 of the packing ring 12 is most
preferable. This is because a space 17 created between the
converged trapezoid 16 and the side wall of the groove 11 can
accommodate the expanded portion of the packing ring 12 caused by
deformation when the ring 12 is pressed into the groove 11 by the
screw engagement of the cap nut 5 with the valve body 1, whereby a
tighter seal can be achieved.
As stated above, according to these embodiments there is no gap
between the opposed end surfaces of the union 3 and of the body cap
4.
According to a fifth embodiment of the present invention, the ball
valve further comprises, in addition to the abovesaid cavity-free
construction, means for screwing the union rotative to the valve
body which is also cavity-free. As illustrated in the foregoing
drawings, the ball valve of the embodiments as well as that of the
prior art has another O-ring 18 for sealing between the valve body
1 and the union 3. The O-ring 18 is accommodated in an annular
groove 19 recessed on the circumference of the union 3, over which
the inside wall of the valve body 1 is placed in a water-tight
manner. Therefore, there exists a considerable frictional force
between the O-ring 18 and the union 3, which resists the easy
screwing of the union 3 relative to the valve body 1 and requires a
suitable means for rotating the union 3.
Such a means in the prior art valve comprises dents provided on the
inside wall of the union, as described before. Contrary to this,
according to a fifth embodiment of the present invention shown in
FIGS. 8 and 9, four dents 20 are recessed on the circumference of a
flange portion 23 of the union 3 attached to the outer end thereof.
Since the dents 20 are disposed far from the liquid passage through
a seal formed by the packing ring 12, the dents 20 constitute no
cavity having a tendency to entrap the liquid. The union 3 can be
screwed into or out of the valve body 1 by the application of a
special tool 21 (as shown in FIG. 10) so that projections 22
thereof engage the dents 20 and, by rotating the tool 21, the union
3 may be turned in the clockwise or anti-clockwise direction. The
number of the dents 20 may be at least one, though four are
preferable when the tool 21 is to be used. Each dent 20 is
preferably located on the flange portion at an equi-angular
distance.
As stated above, the ball valve according to the present invention
eliminates cavities from the construction thereof, which cavities
tend to entrap the liquid in the passage way during liquid
transportation. Thereby, even when utilized in the food industry,
the valve is always kept clean and free from any contamination
caused by the putrescence of the liquid.
It is to be understood that the present invention may be embodied
in other specific forms without departing from the spirit or
essential characteristics of the present invention. The preferred
embodiments are therefore to be considered illustrative and not
restrictive. The scope of the invention is indicated by the
appended claims rather than by the foregoing descriptions and all
changes or variations which fall within the meaning and range of
the claims are therefore intended to be embraced therein.
* * * * *